Pasilalinic-sympathetic compass

The device was developed by French occultist Jacques-Toussaint Benoît (de l'Hérault), with the supposed assistance of an American colleague, Monsieur Biat-Chrétien[2][note 1] in the 1850s.

This fluid forms an invisible thread that keeps the snails in "sympathetic communication" by using animal magnetism similar to an electric current pulsating along it.

Benoit persuaded Monsieur Triat, manager of a Paris gymnasium, to give him lodgings and an allowance, having impressed upon him the importance of his discovery.

[4] However, the transmission was inaccurate, with him supposedly receiving errors such as “gymoate” instead of “gymnase”,[5] and he continually walked between the two devices,[4] claiming that it was necessary to supervise his assistants to ensure that they were touching and reading the snails correctly.

[9][4] During the 1871 uprising in the Paris Commune, the need to send and receive secured messages prompted a revival of the idea by Marquis Rochefort, president of the barricades commission.

[12] Along with the Allix article in La Presse the story of the pasilalinic-sympathetic compass was covered by the 1889 book Historic Oddities and Strange Events by Sabine Baring-Gould.